436
FXUS63 KMQT 301348
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
948 AM EDT Sun Jun 30 2024

.KEY MESSAGES...

- Rip currents and dangerous swimming conditions will be possible at
Lake Superior beaches of Alger and Marquette counties through this
afternoon.

- Dry weather Sunday morning through Monday evening under high
pressure.

- Next rounds of showers and thunderstorms arrive Monday night,
continuing into Wednesday. Gusty southerly winds are also expected
Tuesday.

- Warm and wet pattern expected to continue well into July.

&&

.UPDATE...
Issued at 948 AM EDT Sun Jun 30 2024

The forecast remains on track this morning. Temperatures
overnight bottomed out in the lower 40s for most of the area,
but throughout the western UP, some pockets dropped as low as
the mid 30s with Watton (in Baraga county) the winner at 34F.
Given that we will likely be coming in a couple degrees cooler
across much of the UP into early Monday morning, temperatures
will continue to be the primary concern for the near-term
forecast. Will not rule out some spots seeing some frost
tonight. Stay tuned!

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 336 AM EDT Sun Jun 30 2024

Strong subsidence can be seen overspreading Upper Michigan early
this morning per water vapory imagery and surface analysis
indicating 1027 mb high pressure over the Dakotas/Minnesota. So,
any lingering rain showers have since tapered off over the last
few hours, and ground-based obs are indicating clearing across
the western quadrant and Keweenaw Peninsula already this
morning. This will be conducive to decent radiational cooling
and portions of the interior west dipping into the upper 30s
over the next several hours. And, despite ample sunshine today,
high temperatures will remain below normal with widespread 60s
(interior) in the northwesterly flow. Lakeshores will be even
cooler in the upper 50s. Tonight, as the aforementioned high
pressure becomes centered overhead, even stronger radiational
cooling and calm winds will lead to more lows in the upper
30s/low 40s along with a threat for patchy frost, which will
continue to be monitored.

In addition, dangerous swimming conditions for Marquette and Alger
counties are expected again through this afternoon.  And, a Beach
Hazards statement will follow shortly.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 305 AM EDT Sun Jun 30 2024

Long term period, beginning Monday, kicks off with a 1027mb surface
high overhead while mid-upper level ridging extends from the Gulf of
Mexico northward through the region. This will support a dry day,
but the next system moving closer will support increasing cloudiness
in the west by afternoon. Daytime highs should climb into the 70s.

Upstream on Monday, broad troughing will exit the northern Rockies,
moving into the northern Plains and lifting a shortwave through the
region by Monday night into early Tuesday. Increasing isentropic
ascent will support rain lifting into the west overnight. Some
thunderstorms can`t be ruled out given the elevated instability
characterized by 200-500 j/kg MUCAPE. As Tuesday progresses, ridge
of theta-e advection moves through the region enabling the initial
swath of rain to shift east. This while a stout 35-45kt 925mb LLJ
moves through as well. Similarly to Monday night, thunderstorms
can`t be ruled out given the elevated instability, but severe
weather is not expected. The LLJ will likely support a breezy day,
particularly on the downslope spots near Lake Superior. EFI and
SOT highlight the abnormality of this wind as it relates to the
climate record and the EC ensemble system suggests a 50+%
chance of 34kt gusts in the high terrain and downslope spots in
Alger, Marquette, and Baraga counties. Additionally, the same
suggests the higher wind potential in Gogebic County.

Expect a break in the rain by afternoon from west to east. The last
slug of moisture and the system`s cold front presses through
overnight Tuesday and Wednesday, finally clearing eastern Upper
Michigan sometime Wednesday afternoon. Over the course of the entire
event, deterministic EC suggests 0.5-1.5 inches of rain may fall
while the GFS appears to be more tampered. With this being said,
both their ensemble systems suggest the south-central and east would
be most favored (20-50% chance) for these higher rain amounts. High
pressure and a dry start 4th of July follow, but afternoon showers
and thunderstorms may develop by afternoon in the west ahead of hte
next system moving in. This system looks to press into the Upper
Great Lakes Thursday night through Friday. There`s enough
differences in the timing of this system to make me uncertain on
when the rain will end Friday and its possible it may persist into
the evening hours.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 734 AM EDT Sun Jun 30 2024

VFR conditions to prevail for duration of TAF period with high
pressure over the region.

&&

.MARINE...
Issued at 305 AM EDT Sun Jun 30 2024

Pressure rises and cold air advection should gradually weaken early
this morning, enabling winds to begin settling across Lake Superior.
Expecting winds below 20kts to return lake-wide by mid-late morning.
High pressure begins sliding in from the west through the day,
maintaining these light winds through at least Monday.

Another system presses in from the west Monday night, bringing with
it waves of rain and maybe some thunderstorms, into Wednesday. These
rain showers may support fog developing and periods of low
visibility on the lake. A stout 925mb low level jet of 35-45 kts
will also come with this system. This will support increasing
southerly winds Monday night into Tuesday. Internal probabilistic
tools suggest a low probability (<25%) that these stronger winds
will mix down to the surface, and there`s some validity to this
given the increasingly warm airmass and stability over the lake at
the time. With this being said though, localized terrain driven
influences should support small pockets of mixing down low end
gales, particularly downwind of the lakeshores east of Marquette and
along the northern shores of the Keweenaw. Latest EC ensemble system
suggests a 10-30 percent chance of low end gales north and east of
the Keweenaw over the open waters. Given the setup and the consensus
of the strength of the low level jet, I suspect these percentages
will increase as we approach the event. Another slug of moisture
will lift through Tuesday night into Wednesday while winds settle
down. The cold front presses through west to east through the day
Wednesday, allowing winds to become westerly/southwesterly through
the day Wednesday. Another period of stronger winds, upwards of 25-
30kts, looks possible between the Keweenaw and Isle Royale Wednesday
in this southwesterly flow. High pressure and light winds return
Wednesday night into Thursday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 6 PM EDT this evening for MIZ005-
     006.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

UPDATE...
SHORT TERM...TDUD
LONG TERM...JTP
AVIATION...TDUD
MARINE...JTP